This invention relates to the effective use of aircraft trailing ground lines. In one of its aspects the invention is concerned with visibility problems presented by the use of trailing ground lines. In another aspect the invention pertains to means overcoming aircraft trailing ground line utilization problems.
Aircraft trailing ground lines are those pendant arms used on helicopters, and some fixed wing aircraft, such as rescue lines, load hook lines, fuel lines, disaster platforms and the like used in refueling, rescue missions, cargo carrying and similar tasks.
In rescuing victims from such disasters as burning buildings with rescue lines or platforms, or in in-flight refueling, and on hooking cargo hooks onto load rings, it is difficult to align the lines, platforms, hooks, or hoses, herein referred to as trailing ground lines, with the objects the trailing ground lines are working with, such as fuel tanks, load rings, and windows, because the trailing ground lines are hanging from the aircraft bottom and cannot be seen by the aircraft crewmen. Current equipment and methods for using trailing ground lines have evolved from the need to meet demands as they arose. These presently used procedures are hazardous and difficult to carry out. Generally, a person beneath the hovering helicopter or in another aircraft must signal the pilot. Frequently it became a matter of the helicopter pilot swinging the lines to the person below. Usually that person then must manually connect or hold the ground line in place. It is a challenge for the pilot to maintain the proper position of his aircraft by means of voice directions and visual cues. Under normal visual conditions, the task is not easy. Under low visibility conditions the task can become very dangerous, and seriously compromise mission effectiveness. Moreover, the use of these methods under instrument meteorological conditions is beyond the capability of the current inventory aircraft with procedures now in use.
A number of studies have been made to determine various conceptual approaches to load acquisition problems. With some measure of success visual augmentation systems have been attempted, for example, closed circuit television apparatus. However, such systems are expensive and present depth perception problems. This invention provides a full field of view for a pilot or other crewman remotely situated from the working end of the trailing ground line, and also an enlarged field of view focusing on the object the line is coupling with. The coupling, whether a platform adjacent a window, a hose in a fuel tank or a hook in a load ring, can be accomplished without help from below. More important coupling is possible under instrument flying conditions where television viewing is not feasible.